It's not really clear what you are asking for - a dress pattern? "Native American" covers all the native peoples of the Americas, from the far north of Canada to the southernmost tip of South America, over a period of 20,000 years. Since your event sounds like the popular fantasy image of "cowboys and Indians", perhaps you are thinking of a particular Plains tribe of the 19th century?

"Traditional" native clothing did not include wedding dresses, although women probably would wear a newly-made set of dress, leggings and moccasins for such an occasion. Many tribes never had any special ceremony for marriage - the couple simply moved into a new home together.

Plains women, such as the Blackfoot tribes (Blood, Blackfoot and Pikuni), originally wore dresses of very soft, brain-tanned buckskin (deer or antelope, sometimes mountain sheep or mountain goat), decorated with either dyed porcupine quills or glass beads obtained from white traders. Towards the end of the 19th century they began wearing cloth dresses (with material also obtained in trade) that were decorated in just the same way. A properly-beaded dress represents weeks of work and a huge number of beads:

blackfoot dress.jpg (11.84 KiB) Viewed 1741 times

blackfoot dress beadwork.jpg (27.56 KiB) Viewed 1741 times

The cloth dresses always look "poor" in comparison, even when decorated:

blackfoot cloth dress.jpg (14.86 KiB) Viewed 1741 times

Edit: I should have mentioned that the sleeves on both buckskin and cloth dresses were not sewn up along the lower edge - some writers refer to them as "wings" rather than true sleeves.

Thanks that will be ideal I found a pattern like the photo in town today I will probably use cotton and do as much bead work on it as I can. Just waiting for the first meeting and a deposit and I will start.

if you are going with 'quality dressing up' rather than 'specific place and time' level of accuracy, you might find chamois a good economical substitute for buckskin. Both are oil tanned and chamois has a good drape and takes beading well.Perhaps a tunic in that and the cloth for a skirt would be a good compromise of time/cost/effect